The invention relates to guides for supporting elongated rotary elements, especially in metal working operations.
Certain metal working operations involve the longitudinal feeding of a long, narrow metal workpiece into a metal working machine, such as a single or multiple spindle automatic turning machine or other types of metal working machinery. These machines gradually advance the workpiece longitudinally while rotating the workpiece at high speed about its own longitudinal axis. The workpiece is supported along its length, e.g., by means of tubing through which the workpiece passes.
Due to its high rate of rotation, the workpiece tends to undergo a whipping action in which it is urged radially outwardly by centrifugal force and comes into contact with the inner surface of the tubing. The resulting noise is of such a high level as to constitute a health hazard to proximate operators.
Efforts to reduce the noise level have included the insertion of sound-damping plastic liners inside the steel tubes, or utilizing a specially designed tube in which the stock turns within pressurized hydraulic oil. Although those efforts have been somewhat helpful, the plastic insert tubes wear out, and the hydraulic pressurized tubes are costly.
A guide apparatus has previously been proposed in Reichl U.S. Pat. No. 2,686,444 in which three guide rolls are arranged for displacement toward and away from a rotary workpiece which extends through the guide. Two of the rollers are carried by crank levers which are pivoted on a stationary housing. The third roll is mounted on a reciprocating frame which is connected to the crank levers by gear teeth so that the levers are rotated toward the workpiece in response to reciprocating of the frame. Such a structure is relatively complex in that it requires the use of gear teeth and a heavy duty actuator for reciprocating the relatively heavy frame.
Therefore, it would be desirable to provide a relatively simple and inexpensive guide which supports a rotating/advancing workpiece along its length in a manner permitting the workpiece to rotate freely at high speed without moving radially. The guide should also be adaptable to workpieces of different cross-sectional sizes, and preferably be able to accommodate workpieces of non-circular cross-section.